The present invention relates to a valve for controlling the level of liquid pumped into a vessel and is more particularly directed to apparatus for controlling the circulation of hydroponic solution to and from containers for plants.
In the hydroponic method of cultivation plants are raised in a soil-free environment by means of periodic exposure of the plant root systems to a hydroponic solution containing nutrients, pesticides, fungicides and the like. The plants are typically supported in a container by burying the root systems in an inert medium such as gravel, and the necessary nutrients for plant growth are provided by intermittently flooding or flushing the root systems with hydroponic solution for a controlled, usually short, period of time.
Hydroponic irrigation systems could be especially useful for maintaining decorative plants in homes or in commercial establishments such as restaurants and offices. They have heretofore been rarely used in these settings, however, because of the particular difficulties encountered in circulating the hydroponic solution. Such systems must be capable of serving containers of different sizes, located at different elevations in arrangements dictated by aesthetic appeal. Each container must be filled with hydroponic solution to its own predetermined level and then drained shortly thereafter. The filling and draining of the plant receptacles in this manner must be repeated on a regular basis. Furthermore, it is desirable for decorative use in commercial establishments not primarily concerned with plant cultivation that the system be capable of operating for extended periods with low maintenance and little supervision. In fact, the capability of a system to provide maintenance-free plant receptacles allows the placing of hydroponically grown plants in inaccessible areas, such as under skylights or suspended from ceilings, where even the weekly or semi-weekly watering of conventionally grown plants would be difficult.
Hydroponic irrigation systems for use in the aforementioned settings are presently prohibitively expensive because each plant container must be provided with its own pump and level control. Otherwise plant containers that fill quickly, such as those having small volume or those located close to the reservoir or at lower elevations, will overflow before containers that fill more slowly are adequately flooded with hydroponic solution. Although prior art devices have been developed to regulate the circulation of hydroponic solution, none adequately solves the aforementioned problems peculiar to decorative plant displays.